B-Cell- and Myocyte-Specific E2-Box-Binding Factors Contain E12/E47-Like Subunits

Abstract

Recent studies have identified a family of DNA-binding proteins that share a common DNA-binding and dimerization domain with the potential to form a helix-loop-helix (HLH) structure. Various HLH proteins can form heterodimers that bind to a common DNA sequence, termed the E2-box. We demonstrate here that E2-box-binding B-cell- and myocyte-specific nuclear factors contain subunits which are identical or closely related to ubiquitously expressed (E12/E47) HLH proteins. These biochemical data suggest a pleiotropic function for E12/E47-like molecules in mammalian differentiation, similar to the genetically defined function of daughterless in Drosophila development.